Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * Copyright (c) 2010 Patrick McHardy <kaber@trash.net>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9#include <linux/module.h>
10#include <linux/gfp.h>
11#include <linux/skbuff.h>
12#include <linux/netfilter_ipv4/ip_tables.h>
13#include <linux/netfilter_ipv6/ip6_tables.h>
14#include <linux/netfilter/x_tables.h>
15#include <linux/netfilter/xt_CT.h>
16#include <net/netfilter/nf_conntrack.h>
17#include <net/netfilter/nf_conntrack_helper.h>
18#include <net/netfilter/nf_conntrack_ecache.h>
19#include <net/netfilter/nf_conntrack_zones.h>
20
21static unsigned int xt_ct_target(struct sk_buff *skb,
22 const struct xt_action_param *par)
23{
24 const struct xt_ct_target_info *info = par->targinfo;
25 struct nf_conn *ct = info->ct;
26
27 /* Previously seen (loopback)? Ignore. */
28 if (skb->nfct != NULL)
29 return XT_CONTINUE;
30
31 atomic_inc(&ct->ct_general.use);
32 skb->nfct = &ct->ct_general;
33 skb->nfctinfo = IP_CT_NEW;
34
35 return XT_CONTINUE;
36}
37
38static u8 xt_ct_find_proto(const struct xt_tgchk_param *par)
39{
40 if (par->family == NFPROTO_IPV4) {
41 const struct ipt_entry *e = par->entryinfo;
42
43 if (e->ip.invflags & IPT_INV_PROTO)
44 return 0;
45 return e->ip.proto;
46 } else if (par->family == NFPROTO_IPV6) {
47 const struct ip6t_entry *e = par->entryinfo;
48
49 if (e->ipv6.invflags & IP6T_INV_PROTO)
50 return 0;
51 return e->ipv6.proto;
52 } else
53 return 0;
54}
55
56static int xt_ct_tg_check(const struct xt_tgchk_param *par)
57{
58 struct xt_ct_target_info *info = par->targinfo;
59 struct nf_conntrack_tuple t;
60 struct nf_conn_help *help;
61 struct nf_conn *ct;
62 int ret = 0;
63 u8 proto;
64
65 if (info->flags & ~XT_CT_NOTRACK)
66 return -EINVAL;
67
68 if (info->flags & XT_CT_NOTRACK) {
69 ct = nf_ct_untracked_get();
70 atomic_inc(&ct->ct_general.use);
71 goto out;
72 }
73
74#ifndef CONFIG_NF_CONNTRACK_ZONES
75 if (info->zone)
76 goto err1;
77#endif
78
79 ret = nf_ct_l3proto_try_module_get(par->family);
80 if (ret < 0)
81 goto err1;
82
83 memset(&t, 0, sizeof(t));
84 ct = nf_conntrack_alloc(par->net, info->zone, &t, &t, GFP_KERNEL);
85 ret = PTR_ERR(ct);
86 if (IS_ERR(ct))
87 goto err2;
88
89 ret = 0;
90 if ((info->ct_events || info->exp_events) &&
91 !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events,
92 GFP_KERNEL))
93 goto err3;
94
95 if (info->helper[0]) {
96 ret = -ENOENT;
97 proto = xt_ct_find_proto(par);
98 if (!proto) {
99 pr_info("You must specify a L4 protocol, "
100 "and not use inversions on it.\n");
101 goto err3;
102 }
103
104 ret = -ENOMEM;
105 help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
106 if (help == NULL)
107 goto err3;
108
109 ret = -ENOENT;
110 help->helper = nf_conntrack_helper_try_module_get(info->helper,
111 par->family,
112 proto);
113 if (help->helper == NULL) {
114 pr_info("No such helper \"%s\"\n", info->helper);
115 goto err3;
116 }
117 }
118
119 __set_bit(IPS_TEMPLATE_BIT, &ct->status);
120 __set_bit(IPS_CONFIRMED_BIT, &ct->status);
121out:
122 info->ct = ct;
123 return 0;
124
125err3:
126 nf_conntrack_free(ct);
127err2:
128 nf_ct_l3proto_module_put(par->family);
129err1:
130 return ret;
131}
132
133static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par)
134{
135 struct xt_ct_target_info *info = par->targinfo;
136 struct nf_conn *ct = info->ct;
137 struct nf_conn_help *help;
138
139 if (!nf_ct_is_untracked(ct)) {
140 help = nfct_help(ct);
141 if (help)
142 module_put(help->helper->me);
143
144 nf_ct_l3proto_module_put(par->family);
145 }
146 nf_ct_put(info->ct);
147}
148
149static struct xt_target xt_ct_tg __read_mostly = {
150 .name = "CT",
151 .family = NFPROTO_UNSPEC,
152 .targetsize = sizeof(struct xt_ct_target_info),
153 .checkentry = xt_ct_tg_check,
154 .destroy = xt_ct_tg_destroy,
155 .target = xt_ct_target,
156 .table = "raw",
157 .me = THIS_MODULE,
158};
159
160static int __init xt_ct_tg_init(void)
161{
162 return xt_register_target(&xt_ct_tg);
163}
164
165static void __exit xt_ct_tg_exit(void)
166{
167 xt_unregister_target(&xt_ct_tg);
168}
169
170module_init(xt_ct_tg_init);
171module_exit(xt_ct_tg_exit);
172
173MODULE_LICENSE("GPL");
174MODULE_DESCRIPTION("Xtables: connection tracking target");
175MODULE_ALIAS("ipt_CT");
176MODULE_ALIAS("ip6t_CT");